Design and Development of a Conjoined Narrow Wall Slotted Waveguide Array Antenna with Low Side Lobe Levels

This paper discusses the development of a multipiece narrow wall slotted waveguide array antenna (SWAA) for the X-band frequency range (9.1 GHz - 9.5 GHz). Slots were cut on the narrow wall, and the SWAA operates as a travelling wave type. Slot angles were calculated via polynomial equations, whereas slot depths were determined on the basis of fixed resonance lengths corresponding to slot angles. A 54-slot prototype was developed by joining three waveguide pieces and then cutting the slots. The fabricated prototype was tested for both bench-level measurements and radiation pattern parameters, achieving a return loss better than -34 dB, an insertion loss better than -12 dB, and a side lobe level better than -25.2 dB at 9.3 GHz.